Can Drum Machines Sound Human?

So I’m into drummers. I’ve got my favorites.

One who kind of flies under the radar is Jeff Porcaro, the drummer for Toto, but an extremely accomplished session musician. As Wikipedia quotes, his drumming pretty much defined late-70s and 80s pop.

In 1982, Michael McDonald released I Keep Forgettin’. The track is smooth, soulful, and unforgettable—but ask any drummer and they’ll tell you the real star isn’t McDonald’s voice. It’s Jeff Porcaro’s hi-hat. With one hand, Porcaro delivered a flowing 16th-note pattern that felt alive, groovy, and impossible to copy exactly.

Here’s the song. It’ll probably sound familiar.

And here’s the isolated drum track

Decades later, scientists cracked open this beat with high-tech analysis tools. What they found wasn’t just a quirky detail about a single song. It’s a window into why music makes us move—and why “perfect” machine timing might actually kill the groove.

Wait… Drums Can Be Fractal?

Here’s the twist: Porcaro’s hi-hat pattern behaves like a complex system—the same way heartbeats, stock markets, and even rainfall do. Scientists discovered his timing wasn’t perfectly steady like a metronome. Instead, it wobbled in fascinating ways:

• Long-range correlations: Over time, the tiny variations in Porcaro’s hits followed patterns that stretched across whole phrases of the song.
• Short-range anticorrelations: On a hit-by-hit level, if one note came in a hair late, the next was slightly early, almost like a correction mechanism.

Together, these fluctuations created a rhythm that was structured yet never robotic. In scientific terms, the beat exhibited 1/f noise—sometimes referred to as “fractal noise.” In musical terms, it gave the song a heartbeat.

Why Listeners Love the “Human Touch”

Here’s where it gets really wild: studies show people prefer music with these subtle imperfections. When researchers compared “humanized” beats with mathematical randomness, listeners consistently rated the fractal-like beats as more enjoyable, more groovy, and more moving.

Think about it. A drum machine can hit every note with robotic precision, but something feels off. It’s too stiff. Our brains crave a balance of predictability and surprise. Porcaro’s drumming—whether he knew it consciously or not—hit that sweet spot.

A Detective Story in Sound

To pull this off, scientists didn’t just tap their feet along. They zoomed in with millisecond precision, identifying over 900 hi-hat hits in I Keep Forgettin’. They measured timing, volume, and patterns across bars. The result? A map of Porcaro’s groove that revealed:

• Drift without a metronome: The tempo shifted slightly across song sections, matching lyrical changes almost like emotional shading.
• Two-bar patterns: Every pair of measures formed a unique amplitude signature, beyond the simple accents that drummers typically discuss.
• Microtiming fingerprints: The variations were consistent enough to be “Porcaro’s signature”—like a rhythmic fingerprint.

One of his collaborators, Jay Graydon, once said: “When playing with Jeff, better not to use a click since he played inside the cracks and his time float is what made him great.” Science now agrees.

The Groove vs. the Grid

This study raises a fascinating question: if machines can now copy every tiny wobble and fluctuation, will future drum machines finally “groove” like humans?

It’s not far-fetched. Imagine a drum machine programmed not just with perfect 16th notes, but with Porcaro-style long-range correlations. Every phrase would breathe and sway, making the groove feel alive. Music software could get a major upgrade—one that doesn’t flatten the humanity out of rhythm.

But there’s another takeaway. For drummers, teachers, and anyone who loves playing music: perfection isn’t the goal. Groove lives in the imperfections. Porcaro’s one-handed technique wasn’t just a technical choice—it was a deliberate way to avoid stiffness. In his words: “The alternating stroke method sounded too stiff and staccato for me.”

From Physics to Funk

What’s most mind-blowing is that this research connects Porcaro’s groove to universal laws. The same math that describes your heartbeat also explains why a hi-hat beat feels good. Music isn’t just art—it’s physics meeting biology.

And maybe that’s why we dance. Our bodies recognize patterns that live in everything around us. We’re wired to move with the fluctuations. When Porcaro laid down that hi-hat groove, he wasn’t just playing drums. He was syncing human motion to fractal rhythms of the universe.

Let’s Explore Together

So the next time you tap your foot to a song, ask yourself: is it the singer, the melody, or the microscopic wobble in the rhythm pulling me in? Science says it might be that tiny imperfection.

Now it’s your turn:

• How do you see this research affecting your life? Would you want your Spotify playlists “humanized”?
• If you could teach a drum machine to copy any musician’s groove, who would you pick?

Share your thoughts—we’re listening for the beat.